Related papers: Diffractive $\phi$-meson photoproduction on proton…
As part of a measurement of the cross section of $\phi$ meson photoproduction to high momentum transfer, we measured the polar angular decay distribution of the outgoing $K^+$ in the channel $\phi \to K^+K^-$ in the $\phi$ center-of-mass…
The polarization observables in phi photoproduction are suggested for probing the nucleon strangeness. Based on models for phi photoproduction, some double polarization observables are shown to be very sensitive to the strangeness content…
We report the first measurement of the photoproduction cross section of the $\phi$ meson in its neutral decay mode in the reaction $\gamma p \to p\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \le…
The ALICE Collaboration reports three measurements in ultra-peripheral proton$-$lead collisions at forward rapidity. The exclusive two-photon process \ggmm and the exclusive photoproduction of J/$\psi$ are studied. J/$\psi$ photoproduction…
The photoproduction of omega mesons off protons has been studied at the Bonn ELSA accelerator from threshold to E_gamma = 1700 MeV. Linearly polarized beams were produced via coherent bremsstrahlung. Large photon asymmtries in excess of 50%…
We investigate $\phi$-meson electroproduction off the proton target, i.e., $\gamma^* p \to \phi p$, by employing a tree-level effective Lagrangian approach in the kinematical ranges of $Q^2$ = (0$-$4) $\mathrm{GeV}^2$, $W$ = (2$-$5) GeV,…
Cross sections for elastic and proton-dissociative photoproduction of J/psi mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at $ep$ centre-of-mass energies sqrt{s} approx 318 GeV and…
The LEPS and CLAS data of the incoherent photoproduction of $\phi$ meson from deuteron at low energies are studied with a model for $\phi$ meson photoproduction from nucleon consisting of Pomeron, $\pi$, and $\eta$ meson exchanges in the…
The resonance effects are investigated in the $\phi$ meson photoproduction near threshold through a quark model approach with an effective Lagrangian. The diffractive contribution is consistently estimated by the {\it t}-channel Pomeron…
The process $\gamma p \to \phi p$ close to threshold is investigated focusing on the role played by the {\it s}- and {\it u}-channel nucleonic resonances. For this purpose, a recent quark model approach, based on the $SU(6)\otimes O(3)$…
We consider the reaction $\gamma p \to M p$, with M being either a $\Phi$ or a $J/\Psi$ meson, within perturbative QCD treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to (spatially extended)…
The backgrounds due to the direct diffractive dissociation of the photon into the $\pi^+\pi^-$ as well as $K^+K^-$ pairs to the "elastic" diffractive $\rho '$ and $\phi $ mesons production in electron-proton collisions are calculated. It is…
We have carried out exclusive measurements for the photoproduction of an $\eta$ meson from a proton target with an egg-shaped calorimeter made of BGO crystals (BGOegg) and forward charged-particle detectors at the SPring-8 LEPS2 beamline.…
We report the total and differential cross sections for $J/\psi$ photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold at 8.2~GeV up to 11.44~GeV and over the full kinematic range of…
We present the first measurement at the LHC of exclusive J/$\psi$ photoproduction off protons, in ultra-peripheral proton-lead collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV. Events are selected with a dimuon pair produced either in the…
The diffractive photoproduction of rho mesons, e p \to e rho Y, with large momentum transfer squared at the proton vertex, |t|, is studied with the H1 detector at HERA using an integrated luminosity of 20.1 pb^{-1}. The photon-proton centre…
Observed enhancements in the forward and backward directions for $\phi$ meson photoproduction off nucleons are shown to be explainable by the production of a nonresonant recoiling $(su)$ diquark, $(\bar s ud)$ triquark pair. We show that…
Exclusive electroproduction of $\phi$ mesons has been studied in $e^\pm p$ collisions at $\sqrt{s}=318 \gev$ with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb$^{-1}$. The $\gamma^*p$ cross section is presented in the…
The cross section is estimated for the $\pi^+\pi^-\pi^0$ invariant mass distribution in the $\gamma p$ reaction in the GeV region. This reaction is assumed to proceed through the formation of the $\omega$ meson in the intermediate state,…
Differential cross sections for eta photoproduction off protons have been measured at E_gamma = 1.6 - 2.4 GeV in the backward direction. A bump structure has been observed above 2.0 GeV in the total energy. No such bump is observed in cross…